I have opened a pdf set of plans to do a work up and I need to be able to use the measure tool but no tools are available except for comment. I have acrobat dc pro. Is there a reason I can't access these tools?
You'll find all of the tools by clicking on the Tools collection in the top left region of the main window. Some of the tools are displayed in the right Panel from which you can add or remove the tools you use all the time.
It's pretty easy for one to have both Acrobat Pro and Reader installed... and not know that Reader is the application that's open! On occasion, an OS update, or some other software tweak unrelated to Acrobat has changed the default program for PDFs, and I've ended up in Reader without knowing it over the years. I know it's overly simple, but be sure to look at the top of your program (Title Bar) and confirm that you are in Acrobat Pro, not Reader.